1. Field of the Invention
The present invention relates to a semiconductor bonding apparatus, particularly to a semiconductor bonding apparatus which bonds a semiconductor chip via an elastic member disposed between a semiconductor chip and a mounting substrate.
2. Description of the Related Art
In recent years, optical members such as a lens and mirror have been added to a semiconductor chip or a mounting substrate to be mounted on optical products such as an optical communication apparatus and a microscope, and an optical device has been well developed aiming at reduction of the number of components for use in the whole device, miniaturization of the product, and enhancement of a function. In many of these optical devices, the semiconductor chip has to be bonded to the mounting substrate at an interval which is kept as a predetermined distance in order to effectively fulfill an optical function. There has been a demand for higher precision in the interval to be kept as compared with conventional bonding of the semiconductor chip to the mounting substrate.
For the conventional bonding of the semiconductor chip to the mounting substrate, there is a major demand that a mechanical bonding strength be secured and an electric conduction be obtained. There is little demand that the interval between the semiconductor chip and the mounting substrate be secured at high precision. Therefore, also for the bonding of these devices, a bonding apparatus is hardly seen including a function of controlling a height position of the semiconductor chip or the mounting substrate at a bonding time as a factor which determines the interval between the semiconductor chip and the mounting substrate with the high precision.
As the bonding apparatus which controls the height position of the semiconductor chip, there is a semiconductor manufacturing apparatus described in Jpn. Pat. Appln. KOKAI Publication No. 2002-134563. The semiconductor manufacturing apparatus of the Jpn. Pat. Appln. KOKAI Publication No. 2002-134563 will be described with reference to FIG. 8.
That is, a linear motor 106 which is movable in a vertical direction in accordance with control of a controller 108 is installed in the semiconductor manufacturing apparatus. The linear motor 106 is connected to a mounted nozzle 105 which is capable of holding a semiconductor device 101. Moreover, a position sensor 107 capable of detecting the height of the mounted nozzle 105 is disposed in the vicinity of the mounted nozzle 105. It is possible to position a mounting substrate 102 by a positioning stage 104 on which the mounting substrate 102 is disposed.
In the constitution, first, the mounting substrate 102 is positioned in a horizontal direction by use of the positioning stage 104. Moreover, the controller 108 drives the linear motor 106 to start lowering the mounted nozzle 105 in a state in which the semiconductor device 101 is adsorbed/held by the mounted nozzle 105. Subsequently, the height of the mounted nozzle 105 at this time is measured by the position sensor 107, and the position of the mounted nozzle 105 is controlled to bring soldering bumps of the semiconductor device 101 into contact with the mounting substrate 102.
When the semiconductor device 101 contacts the mounting substrate 102 in this manner, the semiconductor device 101 and mounting substrate 102 are heated by a heater table 103. When the soldering bumps of a bonded portion are molten and liquefied, the soldering bumps are pressed/crushed by a defined amount, and the semiconductor device 101 is positioned in a height direction with respect to the mounting substrate 102. Thereafter, the mounted nozzle 105 is lifted up as if the soldering bumps were stretched.
It is to be noted that in a method of the Jpn. Pat. Appln. KOKAI Publication No. 2002-134563, an upper limit is set on a driving current value to be passed through the linear motor 106 in order to prevent the linear motor 106 from being driven at a certain thrust or more, when moving downwards the mounted nozzle 105.
Separately from the method of the Jpn. Pat. Appln. KOKAI Publication No. 2002-134563, there is a bonding method in which the semiconductor chip is bonded to the mounting substrate via an elastic member disposed between the semiconductor chip and the mounting substrate in order to secure the interval between the semiconductor chip and the mounting substrate at the height position. In the bonding method, the semiconductor chip or the mounting substrate is pressed to deform the elastic member disposed between the semiconductor chip and the mounting substrate, and a pressing force at this time is controlled. Accordingly, deformation of the elastic member is controlled to determine the interval between the semiconductor chip and the mounting substrate.